使用凌空连接到PHP获取JSONObject的响应

Question

public void volley(){ 
    String url = "http://percyteng.com/get_users_details.php"; 

    StringRequest postRequest = new StringRequest(Request.Method.POST, url, 
      new Response.Listener<String>() { 
       @Override 
       public void onResponse(String response) { 
        try { 
         JSONObject jsonResponse = new JSONObject(response).getJSONObject("user"); 
         String useremail = jsonResponse.getString("useremail"), 
           password = jsonResponse.getString("password"); 
         alert(useremail,password); 
        } catch (JSONException e) { 
         e.printStackTrace(); 
        } 
       } 
      }, 
      new Response.ErrorListener() { 
       @Override 
       public void onErrorResponse(VolleyError error) { 
        error.printStackTrace(); 
       } 
      } 
    ) { 
     @Override 
     protected Map<String, String> getParams() 
     { 
      Map<String, String> params = new HashMap<>(); 
      // the POST parameters: 
      params.put("useremail", etUsername.getText().toString()); 
      params.put("password", etPassword.getText().toString()); 
      return params; 
     } 
    }; 
    Volley.newRequestQueue(this).add(postRequest); 

这里是凌空的连接代码，我在我的Android的Java登录分类。我用警报来测试，发现这条线路并不真正起作用。
JSONObject jsonResponse = new JSONObject(response).getJSONObject("user"); 该网址应该是正确的，下面是我的PHP代码。

`$response = array();` 

// include db connect class 
require_once __DIR__ . '/db_connect.php'; 
try{ 
    // connecting to db 

    $con = new DB_CONNECT(); 

    $db = $con->connect(); 
    echo $_POST["useremail"]; 
    // check for post data 

    if (isset($_POST["useremail"]) && isset($_POST["password"])) { 
     $email = $_POST["useremail"]; 
     $password = $_POST["password"]; 
      // $useremail = "percytsy@gmail.com"; 
      // $password= "coolpig123"; 
      // echo "shit"; 
     // get a product from products table using PDO prepared statement 
     $result = $db->prepare("SELECT * FROM user WHERE useremail = :useremail AND password = :password"); 
     echo "shit"; 
     $result->bindParam(":useremail", $useremail, PDO::PARAM_STR, 30); 
     $result->bindParam(":password", $password, PDO::PARAM_STR, 25); 

     // bind the values individually 
     //execute will execute db command with binded variables. Becaise we 
     // binded first, the parameters for eceute() can be empty 
     $result->execute(); 
     if (!empty($result)) { 
      // check for empty result 
      if ($result->rowCount() > 0) { 
       $result = $result->fetch(); 
       $user = array(); 
       $user["useremail"] = $result["useremail"]; 
       $user["password"] = $result["password"]; 
       // success 
       $response["success"] = 1; 
       // user node 
       $response["user"] = array(); 
       array_push($response["user"], $user); 
       // echoing JSON response 
       echo json_encode($response); 

      } else { 
       // no product found 
       $response["success"] = 0; 
       $response["message"] = "No user found"; 
       // echo no users JSON 
       echo json_encode($response); 
      } 
     } else { 
      // no product found 
      $response["success"] = 0; 
      $response["message"] = "Empty result"; 
      // echo no users JSON 
      echo json_encode($response); 
     } 
    } else { 
     // required field is missing 
     $response["success"] = 0; 
     $response["message"] = "Required field(s) is missing"; 
     // echoing JSON response 
     echo json_encode($response); 
    } 
} catch(PDOException $e){ 
    print "Sorry, a database error occurred. Please try again later.\n"; 
    print $e->getMessage(); 
} 
?> 

我通过输入参数之前测试了php代码，并成功连接到我的服务器上的mysql。所以我想应该不会有我的PHP代码的问题。

此外，另一个猜测问题是，我没有做一些基本的sudo apt-get ....在我的服务器的Android和PHP连接，因为这个问题事先发生。但是，我不知道我需要安装什么。

Answer 1

你需要通过传递请求之前调用下面的代码来开始你的乱射：

// Instantiate the cache 
Cache cache = new DiskBasedCache(mContext.getCacheDir(), 1024 * 1024); // 1MB cap 
// Set up the network to use HttpURLConnection as the HTTP client. 
Network network = new BasicNetwork(new HurlStack()); 
// Instantiate the RequestQueue with the cache and network. 
mRequestQueue = new RequestQueue(cache, network); 
// Start the queue 
mRequestQueue.start(); 
// Add request to queue 
mRequestQueue.add(postRequest)